some Q's about my car

My cars been eating alot of gas lately. Ever since the Check Engine light came on it's been eating alot of gas and the engine rapidly heats up at a fast rate. I don't drive it anymore, but before I take it in to get it checked, i was wondering if anybody might have an idea about what's wrong with it. Another thing is, I bought those Xenon HID lights and someone told me that there's some sort of wrap or something to put over your headlights so they apear very blue. Is this true?